Provided by: libexplain-dev_1.4.D001-8_amd64 bug

NAME

       explain_fclose - explain fclose(3) errors

SYNOPSIS

       #include <libexplain/fclose.h>
       const char *explain_fclose(FILE *fp);
       const char *explain_errno_fclose(int errnum, FILE *fp);
       void explain_message_fclose(char *message, int message_size, FILE *fp);
       void explain_message_errno_fclose(char *message, int message_size, int errnum, FILE *fp);

DESCRIPTION

       These functions may be used to obtain explanations of fclose(3) errors.

   explain_fclose
       const char *explain_fclose(FILE * fp);

       The  explain_fclose  function is used to obtain an explanation of an error returned by the
       fclose(3) function.  The least the message will contain is the value  of  strerror(errno),
       but usually it will do much better, and indicate the underlying cause in more detail.

       The errno global variable will be used to obtain the error value to be decoded.

       This function is intended to be used in a fashion similar to the following example:
              if (fclose(fp))
              {
                  fprintf(stderr, "%s\n", explain_fclose(fp));
                  exit(EXIT_FAILURE);
              }

       fp      The original fp, exactly as passed to the fclose(3) system call.

       Returns:
               The message explaining the error.  This message buffer is shared by all libexplain
               functions which do not supply a buffer in  their  argument  list.   This  will  be
               overwritten  by the next call to any libexplain function which shares this buffer,
               including other threads.

       Note: This function is not thread safe, because it  shares  a  return  buffer  across  all
       threads, and many other functions in this library.

       Note: This function may be of little diagnostic value, because libc may have destroyed any
       useful context, leaving nothing for libexplain to work with (this  is  true  of  glibc  in
       particular).  For files that are open for writing, you will obtain more useful information
       by first calling fflush(3), as in the following example
              if (fflush(fp))
              {
                  fprintf(stderr, "%s\n", explain_fflush(fp));
                  exit(EXIT_FAILURE);
              }
              if (fclose(fp))
              {
                  fprintf(stderr, "%s\n", explain_fclose(fp));
                  exit(EXIT_FAILURE);
              }

   explain_errno_fclose
       const char *explain_errno_fclose(int errnum, FILE * fp);

       The explain_errno_fclose function is used to obtain an explanation of an error returned by
       the   fclose(3)   function.    The  least  the  message  will  contain  is  the  value  of
       strerror(errnum), but usually it will do much better, and indicate the underlying cause in
       more detail.

       This function is intended to be used in a fashion similar to the following example:
              if (fclose(fp))
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_fclose(err, fp));
                  exit(EXIT_FAILURE);
              }

       errnum  The  error  value  to  be decoded, usually obtained from the errno global variable
               just before this function is called. This is necessary if you  need  to  call  any
               code  between the system call to be explained and this function, because many libc
               functions will alter the value of errno.

       fp      The original fp, exactly as passed to the fclose(3) system call.

       Returns:
               The message explaining the error.  This message buffer is shared by all libexplain
               functions  which  do  not  supply  a  buffer in their argument list.  This will be
               overwritten by the next call to any libexplain function which shares this  buffer,
               including other threads.

       Note:  This  function  is  not  thread  safe, because it shares a return buffer across all
       threads, and many other functions in this library.

       Note: This function may be of little diagnostic value, because libc may have destroyed any
       useful  context,  leaving  nothing  for  libexplain to work with (this is true of glibc in
       particular).  For files that are open for writing, you will obtain more useful information
       by first calling fflush(3), as in the following example
              if (fflush(fp))
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_fflush(err, fp));
                  exit(EXIT_FAILURE);
              }
              if (fclose(fp))
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_fclose(err, fp));
                  exit(EXIT_FAILURE);
              }

   explain_message_fclose
       void explain_message_fclose(char *message, int message_size, FILE *fp);

       The  explain_message_fclose function is used to obtain an explanation of an error returned
       by the  fclose(3)  function.   The  least  the  message  will  contain  is  the  value  of
       strerror(errno),  but usually it will do much better, and indicate the underlying cause in
       more detail.

       The errno global variable will be used to obtain the error value to be decoded.

       This function is intended to be used in a fashion similar to the following example:
              if (fclose(fp))
              {
                  char message[3000];
                  explain_message_fclose(message, sizeof(message), fp);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

       message The location in which to store the returned message.   Because  a  message  return
               buffer has been supplied, this function is thread safe.

       message_size
               The size in bytes of the location in which to store the returned message.

       fp      The original fp, exactly as passed to the fclose(3) system call.

       Note: This function may be of little diagnostic value, because libc may have destroyed any
       useful context, leaving nothing for libexplain to work with (this  is  true  of  glibc  in
       particular).  For files that are open for writing, you will obtain more useful information
       by first calling fflush(3), as in the following example
              if (fflush(fp))
              {
                  char message[3000];
                  explain_message_fflush(message, sizeof(message), fp);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }
              if (fclose(fp))
              {
                  char message[3000];
                  explain_message_fclose(message, sizeof(message), fp);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

   explain_message_errno_fclose
       void explain_message_errno_fclose(char *message, int message_size, int errnum, FILE *fp);

       The explain_message_errno_fclose function is used to obtain an  explanation  of  an  error
       returned  by  the  fclose(3) function.  The least the message will contain is the value of
       strerror(errnum), but usually it will do much better, and indicate the underlying cause in
       more detail.

       This function is intended to be used in a fashion similar to the following exameple:
              if (fclose(fp))
              {
                  int err = errno;
                  char message[3000];
                  explain_message_errno_fclose(message, sizeof(message),
                      err, fp);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

       message The  location  in  which  to store the returned message.  Because a message return
               buffer has been supplied, this function is thread safe.

       message_size
               The size in bytes of the location in which to store the returned message.

       errnum  The error value to be decoded, usually obtained from  the  errno  global  variable
               just  before  this  function is called.  This is necessary if you need to call any
               code between the system call to be explained and this function, because many  libc
               functions will alter the value of errno.

       fp      The original fp, exactly as passed to the fclose(3) system call.

       Note: This function may be of little diagnostic value, because libc may have destroyed any
       useful context, leaving nothing for libexplain to work with (this  is  true  of  glibc  in
       particular).  For files that are open for writing, you will obtain more useful information
       by first calling fflush(3), as in the following example
              if (fflush(fp))
              {
                  int err = errno;
                  char message[3000];
                  explain_message_errno_fflush(message, sizeof(message),
                      err, fp);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }
              if (fclose(fp))
              {
                  int err = errno;
                  char message[3000];
                  explain_message_errno_fclose(message, sizeof(message),
                      err, fp);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2008 Peter Miller

AUTHOR

       Written by Peter Miller <pmiller@opensource.org.au>

                                                                                explain_fclose(3)